Baker's Dozen Solitaire is a type of patience game played with one deck of standard 52-cards set which has no stock pile. All cards are dealt face-up at the beginning to 13 columns with aim to build four foundation piles up from Ace to King. Only the top card of a column is available for play.

The difference between the variants are as following
Baker's Dozen - Cards in a tableau pile are build-down by rank in any suit. Empty tableau pile can not be filled with any card.
Spanish Patience - Cards in a tableau pile are build-down by rank in any suit. Empty tableau pile can be filled with any card.
Castles in Spain - Tableau piles are build-down by alternate colors. Empty tableau pile can be filled with any card.
Portuguese Solitaire - Cards in a tableau pile are build-down by rank in any suit. Empty tableau pile can only be filled with a King.

Features
- Save game state to play later
- Unlimited undo
- Game play statistics